Grissom also drops the news on his CSI cohorts that he's seeking less gruesome pastures, which sparks a variety of reactions (probably not dissimilar to the ones Petersen met when he announced he was leaving his sure-thing hit series). As for exactly how the farewell will play out, one more bit of bad news: tonight's installment is the beginning of a two-parter, which doesn't conclude until 2009.

Grissom also drops the news on his CSI cohorts that he's seeking less gruesome pastures, which sparks a variety of reactions (probably not dissimilar to the ones Petersen met when he announced he was leaving his sure-thing hit series). As for exactly how the farewell will play out, one more bit of bad news: tonight's installment is the beginning of a two-parter, which doesn't conclude until 2009.

'30 Rock' (9:30PM, NBC) Jack feels like sharing his holiday spirit (which has been crushed by the appearance of his overbearing mother), so he makes Liz and her staff cancel their holiday plans to put together a last-minute Christmas special.

'The Office'(9PM, NBC) She's had her pelvis broken by Michael, she's traded sex for Outback Steakhouse coupons and she's so addicted to alcohol that she drank Angela's hand sanitizer. Tonight, the hapless Meredith becomes the butt of another mishap when her hair catches on fire at Phyllis' holiday party.

'Celebrity Rehab With Dr. Drew'(10PM, VH1) 2nd season finaleFor once, it's not Jeff causing a ruckus at the Pasadena Treatment Center, but it is another season one rehabber -- Seth "Shifty" Binzer -- who checks back in, and isn't happy about the second time around.

'The Sarah Silverman Program'(10:30PM, Comedy Central) 2nd season finaleSarah doesn't believe in the sanctity of marriage. Which is why she gets engaged to Doug. Her dog.

'ER'(10PM, NBC) Consider this a bah humbug zone: Sam is worried about removing Alex from the respirator after his accident, Morris gets an unwanted package from his father and a woman in the midst of a high-risk pregnancy is about to be deported.